SuperComputing 2013 has been the occasion for BSC’s research group in heterogeneous architectures, led by Dr Alex Ramirez, to unveil a third prototype of Mont-Blanc exascale design associating power and energy efficiency. What do we find at the core of the machine? Low-power CPUs and GPUs, unsurprisingly of the very same kind as those that equip our mobile devices. This time, BSC chose to use Samsung Exynos APUs combining a dual-core ARM Cortex-A15 CPU to a Mali-T604 GPU on the same die. From an integration standpoint, This is a significant step forward in comparison to Pedraforca, the previous prototype unveiled last year, which contained twice less powerful quad-core Cortex-A9 CPUs (NVIDIA Tegra 3’s) and used a separate NVIDIA Kepler K20 accelerator for parallel computations.

The new cluster also has the particularity of being designed around the Bullx B505 rack blade system and the corresponding new energy efficient chassis system developed by Bull. Each of the six clustered chassis contains nine blades which in turn house fifteen Mont-Blanc calculation cards. Globally, the 1620 ARM cores + 810 Mali GPUs offer a peak performance of 26 Tflops for 50% less electricity consumption than Pedraforca, a single blade delivering in excess of 485 Gflops for 200 Watts. But it is probably with the next iteration, which will feature the already available 64-bit ARM v8 CPU, that this design’s energy efficiency will take on its full meaning. Thanks to a new 8.1 M€ funding envelope from the European Commission, the project is assured to continue for at least two additional years.